I don't know if it's important, but I try to do it anyway.
Coincidentally, I went for an interview today. They had a few questions that I had to answer on a white board. In PHP, I indented my lines, ended them with the obligatory ; and even went back and corrected spacing and re-wrote entire lines to make it look good on the whiteboard.
Did it help? We'll see I guess - but I like my code to look good, be it as actual code or brain storming on a whiteboard.